L-jetronic mods

[James Seabolt]

"James Montebello" <jamesm at talarian.com> wrote:

>Around '80 - '81, the Fiat Spider was sold with a turbo in this
>country.  It was, as I recall, an option added by the US importer,
>not a factory item.  The same L-Jet was used, albeit recalibrated.
>I'd try and scare up some data on this conversion.  I'd guess that
>the conversion parts couldn't have been all that expensive or
>exotic, given the origin, nor could I imagine extensive 
>modifications were done to the L-Jet to get it to work.

I can tell you everything they did to it. They ran 6 pounds of boost and a
really small turbo.

Installed four sets of boost switches:

#1) added 1700 ohms resistance at 1PSI to the coolant temperature circuit
#2) added an additional 500 ohms at 5PSI 

#3) closed the contacts in the TPS at 1 pound (which dumps even more fuel)
#4) overboost switch which did something at 9 pounds

Installed INOX head gasket which has stainless steel inserts instead of
copper. Despite being a little thicker I think this only dropped the C/R
from 8.1:1 to 7.9:1 not much.

Next thing they did was alter the advance curve from 28 degrees total
advance to 10 degrees total advance. All they did was install a fixed clip
in place of one of the springs. This really effect horsepower.

That's it.

The end result was an extra 18 horses! Just 18 horses at 6 pounds of boost.
In theory 7 pounds equals 50% more power so the car should have went from
102 to at least 140.

Some owners complained that when the boost switches kicked in, this dumped
way to much fuel into the motor at once.

Also the retarded timing caused the cast iron exhaust manifolds to warp. No
oil cooler either.

The Warner ISI turbo had a life expectantcy of no more than 20,000 miles.

This is a good example of how not to design a turbo system. I think there
was roughly 800 conversions done, most of which were converted back to
original.


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James Seabolt -----> mailto:jseabolt at intermediatn.net
Webpage: http://users.intermediatn.net/jseabolt/
ICQ # : 7344463

United States

1980 FIAT 2000 TURBO Spider injected (John Deere aspirated)
1981 FIAT 2000 Spider (Rest in Pieces)
1981 FIAT X 1/9 (Injected)
1994 JEEP Wrangler (2.5l )
1976 Chevrolet Pickup (454 Big block/7.3 liter) 
     
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